Engenharia mecanica

Welding processes

The welding processes that may be used in the construction of vessels under this parto f these divisions are restricted as follows: 1- arc welding processes: atomic hydrogen, electro gas, gas metal arc, gas tungsten arc, plasma arc, shielded metal arc, stub, and submerged arc; 2- other than arc welding processes: electron beam, flash, electroslag, explosive*, induction, inertia and continuous drive friction, laser beam, oxyfuel gas, resistance, and thermit. B – other than pressure inherent to the welding processes, no mechanical pressure or blows shall be applied except as permitted for peening in UW-39. C – Defitions are given in section IX which include variations of these processes. D – Arc stub welding and resistance stub welding may be used only for nonpressure-bearing attachments, having a load or nonload-carrying function, except for material listed in Table UHT-23 provided that, in the case of ferrous materials, the heat treatment requirements of UCS-56 are complied with and the requirements of UW-28 (B) and UW-29 (A) are met prior to start of production welding. Studs shall be limited to 1 in. (25mm) diameter maximum for round studs and an equivalent cross-sectional area for studs with other shapes. E – The electros lag welding process may be used for butt welds only in ferritc steels and austenitic stainless steels of types listed in UW-5 (D), provided the requirements of UW-11(a)(6) and UW-44-(d) are satisfied. F – the electrogas welding process may be used for butt welds only in ferritic steels and austenitic stainless steels of types listed in UW-5 (d), provided the requirements of UW-11 (a) (6) are satisfied. When a single pass is greater that 1 ½ in (38mm) in ferritic materials, the joint shall be given a grain refining (austenitizing) heat treatment.

UW – 28 QUALIFICANTION OF WELDING PROCEDURE

A) Each procedure of welding that is to be followed in construction shall be recorded in detail